Lock



pwll 2%, 1936. J. F. svoBoDA LOCK Filed April 14, 1934 5 Sheets-Sheet l g, ,750 /10 joe/fz man J. IF. SVOBODA LOCK Filed April 14, 1954 3 Sheets-Sheet 2 pf'il 28, B. 1. F SVOBQDA I 2,@9399126 LOCK Filed April 14, 1934 3 Sheets-Sheet 3 y @10. @am

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Patented Apr. 28, 1936 UNITED STATES PATENT OFFICE LOCK of Illinois Application April ld, i934, Serial No. 720,528

i8 Claims..

This invention pertains to locks oi the rotary cylinder type adapted to be used in a system oi locks in which each lock is constructed so that it may be operated by an individual service key, but includes ieatures permitting several locks oi a group to be operated by a single master key while all locks of a given system are operable by a single grand master key. One object ci the invention is to provide the lock with features permitting the use oi several keys in the manner illustrated. Another object is to secure economy in manufacture; and a further object is to insure a high degree of safety against picking oi the lock.

The invention consists in certain elements and features oi construction as herein shown and described and as indicated by the claims.

'the opposite half oi" the lock structure.

Figure 3 is a transverse sectional view through the lock taken substantially as indicated at lines li--t on Figure l, showing the tumblers in retracted or unlocked position, and showing the individual or service key in section in the lock.

Figure Il is a sectional view similar to Figure 3 showing a master key in section in the lock, adapted :for controlling the operation oi a group of locks oi the system.

Figure 5 is a view in side elevation of the master key.

Figure 6 is a sectional view similar to Figure t showing a grand master key in section for controlling the operation of two or more master keyed groupsoi locks.

meure 'l is a view in side elevation oi the grand master key.

Figure 8 is a sectional view similar to Figure 6 showing another iorm of grand master key in section. adapted ior controlling two ,or more master keyed groups oi locks ofthe system.

Figure 9 is a sectional view through the lock similar to Figure 3, showing a great grand master key in section; and

Figure l is a diagrammatic view illustrating a lock system embodying the present invention.

rli'his lock construction is suitable for use in systems adapted to a large variety of situations, as in institutions of various characters, apartment buildings, schools, hospitals, and industrial plants; but it will be understood that the lock (Gi. 'lli-d6) may be employed as a separate and individual unit or in a more or less elaborate system with other locks oi the same type. according to re quirernents.

'llbe lock illustrated as embodying my present 5 invention is of the rotary cylinder t employing two series of transversely slidable tumbler elements arranged on opposite sides oi the key slot, and for the purpose of carying out my invention to the fullest extent, I have shown the 1o tumbler elements of each lock ci the system as being each provided with two independent keyengaging abutment features which preferably are located in substantially the same planes in the general direction of movement of the tumbler l elements. ln the drawings these key-engaging abutment features are illustrated as transversely extending abutment shoulders ior engagement by cam surfaces of the key, and as a laterally projecting nib for engagement in a si'lnuous groove 2o of the key.

Referring now in detail to the drawings, the locks oi the entire system are or similar construction, and each lock includes a casing, lli, oi annular form, and a rotary cylinder or plug, il, mounted in the casing for rotation therein under the control oi tumbler elements when actuated by a key. Snugly ntted on the reduced rearward end portion ci the casing is a cup-shaped member, it, enclosing the rear end oi the casing. This cup-shaped element is secured to the casing, lli, by a plurality oi depressions (not shown) formed in its side wall and which project into the external annular groove, tde, of the casing. The bottom oi the cup-shaped member is provided with an arcuate slot through which extends al stud indicated in dotted lines at i te, cn which stud is carried a cam block indicated in dotted lines at it, adapted to engage suitable cooperating elements which are to be operated incident to rotation of the cylinder of the lock.

The rotary cylinder is composed of two longitudinally extending sections indicated as it and it, which are approximately semi-circular in cross section, and the outer marginal portions of said sections are spaced apart by longitudinally extending plates, it, as seen in the drawings. Each of the plates is provided with apertures for registering with and mounting on transversely projecting studsI its, oi the cylinder section, it. as seen in Figure 2 oi the drawings. lli'he cylinder sections are secured together with the plates, it, interposed, by a substantially annular ring member, il, forcibly dtted on the reduced annular shoulder formed at the iront end of the cylinder sections, and the rear ends of the cylinder sections are secured together by a retaining ring, I8, forcibly seated on the annular shoulder at the rear ends of the cylinder sections. The cylinder is conned in the casing, I0, by a cap plate, 20, snugly fitted and locked into the outer end of the casing, as seen in the drawings. It will be understood that the cap, 20, is formed with a rectangular key slot, 20a, in alignment with the longitudinally extending key slot IIb, formed by the tumbler elements, for accommodating several different keys for operation of the lock; and further that the cap plate, 20, is provided with means for an interlocking connection with the cylinder so as to be rotatable therewith as a unit.

The cylinder sections are each provided with a series of axially spaced transversely extending slots, I4, and ISC, and the slots of the respective sections are transversely aligned in pairs. Said slots would open into the key slot, IIb, except for the plates, I6, which serve to define the individual transversely extending slots. Slidably mounted for transverse movement in these slots are tumbler elements, 30, which are dimensioned so that when they are engaged by a key, they are moved to positions of adjustment at which their outer extremities liewithin the circular contour of the cylinder, II, so as to permit rotation of the said cylinder in the casing, I0. These tumbler elements when free are yieldingly projected into longitudinally extending grooves, I0d, formed in the inner wall of the casing, I0, for locking engagement therewith and preventing rotation of the cylinder. Said grooves, I0d, are arranged in two diametrically opposite pairs, and the grooves of each pair are spaced apart by a longitudinally extending rib, |08, which serves as the abutment shoulder against which the tumblers react to prevent rotation of the cylinder. These ribs, I0", are substantially the same thickness as the spacing plates, I6, and are in alignment therewith when the cylinder is locked in the casing, as seen in Figure 3 of the drawings, so as to serve as continuations of the surfaces of the plates, I6, in guiding the tumbler elements as they are moved to and from locking position.

The edges of the tumblers opposite the key slot are provided with notches, 30, each having a transverse shoulder, 30h, against which reacts an individual coil spring, 32, the opposite end of the spring abutting against a transversely extending pin, 33, carried by the cylinder section and exf tending into the tumbler notch, 30B, as seen in Figure 3 of the drawings. The tumbler elements and the springs, 32, with their stop pins, 33, are arranged for urging adjacent tumblers of each series in opposite directions into locking engagement with the casing, and said springs also act on the respective pairs of transversely aligned tumblers in opposite relation, that is, the tumbler elements of each pair are urged in opposite directions, as seen in Figure 3 of the drawings.

The edge of each tumbler element adjacent the key slot, I Ib, is provided with an abutment feature, 30, adapted to be engaged by a cooperatively formed cam surface of a key, 35. In the construction shown in the drawings, the abutment feature of the tumbler is in the nature of a transverse shoulder which forms one of the edges defining an elongated notch, 30d, in the inner edge of each tumbler element. These abutment shoulders are disposed within the key slot for engagement by a key, which moves the tumblers in a direction against the reaction of their compression springs, 32, and when these tumbler elements are freed from engagement with the key, the springs, 32, normally urge them in outward direction into locking engagement with the casing, to prevent rotation of the cylinder therein. It is to be understood that these tumbler elements are preferably different from each other, and are formed with each key-operated abutment shoulder, 30, located at one of a plurality of possible predetermined positions from the end of the effective locking shoulder of the tumbler element. which engages the rib, I0", of the casing, and it will also be understood that the key for engaging these surfaces of the tumbler elements will have its contours shaped accordingly. It will be apparent that the compact arrangement of the tumblers in the lock permits making locks of a relatively great number of diierent tumbler combinations, without rendering the locks unduly bulky.

One of the important features of the lock employed in my system consists in constructing and disposing the tumblers in a manner so that the abutment surfaces, 30C, of adjacent tumbler elements of a series are acted upon by a key in opposite relation, and so that the abutment surfaces of the tumbler elements of each transversely aligned pair of tumbler elements of the respective series, as seen in Figure 3 of the drawings, are likewise acted upon in opposite relation, thus in effect, providing four independent sets of tumbler elements. To accommodate this construction, the key, 35, is provided with four independent cam-operating surfaces, 35a, 35h, 35c and 35d, for actuating the independent sets of tumbler elements of the respective series. Each of the cam surfaces of the key is of a sinuous contour, and as may be seen in the drawings, these surfaces are arranged in pairs at opposite edges of the key; and the aligned cam surfaces, 35, 35C, and 35h, 35d, of the respective pairs have the high points of each surface in alignment with the low points of the opposite cam surface of the key.

Each of the notches, 30d, of the tumbler elements is dimensioned so that the shoulder, 30E, opposite the key-actuated abutment shoulder, 30C, is disposed in close proximity to the camoperating edge of the key, opposite the camoperating edge of said key which actuates said tumbler, as seen in Figures 1 and 2 of the drawings. In other words, by Virtue of this construction when a tumbler has been moved to withdrawn position, the shoulder, 30e, opposite the eiective key-operated abutment shoulder, 30, is moved toward the center of the key slot to such a position as to eifectively guard the key-operated abutment shoulder, 306, of the next adjacent tumbler of the series; such a guard shoulder, 30E, in all instances (when the tumbler has been moved to releasing position) will be disposed inwardly a distance beyond the position assumed by the abutment shoulder, 33C, of the next adjacent tumbler of the series, when it has been moved to releasing position. Manifestly it will be extremely difficult to pick a lock so constructed, by reason of the fact that the next adjacent tumbler of the series has to be moved in a direction opposite to the direction of movement of the` first tumbler, and its abutment surface, 30, which is the only surface convenient to be engaged by an implement or tool in picking the lock, will have to be moved outwardly a distance beyond the guard shoulder, 30e, of the rst tumbler, and an attempt to so move the second tumbler after the first tumbler of the series has been so adjusted. will practically always result in moving the first tumbler out of releasing position, back into locking engagement with the cylinder.

The .separating plates, I6, in addition to providing guidance for the tumbler elements, 30, in their transverse sliding movement in the cylinder, lll, are so dlmensioned that their inner marginal edges project into the key slot lib, of the cylinder a. distance normally inwardly beyond the positions of the key-operated abutment shoulders, 30, of the respective tumbler elements when they have been moved to unlocking position, as may be seen in Figure 3. Such an ar rangement further hampers and renders exceedingly dimcult the task of picking the lock, because of the curtailment of the space immediately adjacent the key-operated abutment shoulders oi the tumblers. The inwardly projecting edges of these plates serve as wards and provide guidance for the key, ab, as it is inserted into the lock, and the key is provided with longitudinally extending ward grooves, la', at opposite edges of the key separating the pairs of cam surfaces, the from lab, and the from dbd.

When locks of the character above described are embodied' in a locking system in accordance with my invention, each tumbler element, it, is provided with a. second key-engaging abutment feature, herein shown as a laterally projecting nib, tllh, extending into the key slot, lib, and these nibs are adapted to be engaged by cooperatively formed features of a key. These nibs,

like the abutment shoulders, the, of the tumbler elements, may be located on the respective tumblers for making up various lock combinations for operation by a cooperatively formed individual or service key, and in the present case this second set of abutment features on the tumbler elements is employed for-mastering and grand mastering certain groups of locks of the system. When it is desired to master key, grand master key, or great grand master key certain groups of locks of the type illustrated in Figures l to 3 of the drawings, the abutment shoulders, it, of one series of 4tumbler elements of all locks of a group are identically arranged. In other words, the individual or service key indicated at 3b will dlifer from the individual or service keys of other locks of the group only with respect to the cam surfaces for operating the other series of tumbler elements. For master-keying a group of locks in this system, the second series of key abutment features, dbh, on the changeable series of tumbler elementslare arranged identically in all of the locks of the system. To provide clearance for the nibs, 3th, the service key, ab, is formed with longitudinally extending grooves, 3tlg, in its opposite side walls, as seen in the drawings.`

Figures d and 5 of the drawings illustrate one form of master key which may be used for controlling a certain group of locks of the system, and for such purpose, it will be noted that the key includes cam surfaces, the and tiib, at opposite edges, which correspond to cam surfaces, the and tbc, of the individual or service key, and these surfaces cooperate with the abutment shoulders, it, of the seriesof tumbler elements, Sill, that are identically arranged in all of the locks of the system. The opposite side wall of the key is formed with a. sinuous groove, the, for cooperative engagement with the nibs, lb, of the other series of tumbler elements; and

as above mentioned, this series of nibs is identically arranged in all of the locks of the system. This key, It, like the key, 3b, is also formed with. ward grooves, 40h and 409, at opposite edges oi the key for cooperative engagement with the ward edges of the plates, i6. The side of the key opposite the sinuous groove, 402, is provided with a longitudinally extending groove, 40k, of rectangular cross section, as indicated in Figure d, to provide clearance for the nibs, 30h, on the other series oi tumbler elements, which tumblers are actuated by the cam surfaces, ta and tde, of the key.

Figures and l illustrate one form oi grand master" key for controlling certain master" keyed groups of locks of the system. When the locks are to be grand masterkeyed, the nibs, lith, of both series of tumblers are identically arranged in all of the locks of the entire system. In this construction the key, dii, which is of substantially rectangular cross section, is provided with longitudinally extending slnuous grooves, the and dbb, in its opposite side walls for engagement with the nibs, it, of the respective series of tumbler elements of all of the locks of these master"keyed groups. ils may be seen in the drawings, the key, tti, and the tumbler elements, db, are dimensioned so that the edges of the key do not engage the abutment shoulders, 30C, of any of the tumbler elements of' the locks. Said key, tb, is provided with ward grooves, libc, and ld, at opposite edges for cooperative engagement with the wards of plates, it.

'I'he several masterkeyed groups oi locks of the system may be arranged in several grand masterkeyed groups, which are controlled by a great grand master" key, bil, which will operate all of the locks of the entire system. For this purpose ll have in certain grand masterkeyed groups of locks, reduced the thickness of the inner edge of one of the ward plates, llt, as indicated at ith, in Figures 3 to 6 of the drawings, and the cooperating ward grooves of the respective keys, 35, iid and tb, have been formed to snugly nt said reduced portion of the ward plate. In other grand masterkeyed groups of locks of the system, this reduced portion of the plate has been reversed, as indicated at lli, in Figure 8, and the grandrnaster key, db, as shown in Figure 8, is provided with an oppositely located ward groove, the, Vfor accommodating said reversed reduced edge, itc, of

the ward plate, it, and by virtue of this arrangement, I obtain two diierent groups of grand masterkeyed locks, and the locks of each group are operable by its individual grand master key. It will be apparent that I may obtain additional grand master keyed groups by similarly reducing the ward edge of the opposite ward plate. By virtue of such warding, each key of the lock system may be inserted into the locks in only one position.

In Figure 9 of the drawings I have shown a section of the lock with a great grand master key, bd, in section, for operating all of the locks of the entire system. This key includes sinuous grooves, the and Elib, in its opposite side walls for cooperative engagement with the nibs, dbh, of the tumbler elements which are identically arranged in all of the locks, for withdrawing said tumblers from locking position. The key is also provided with ward grooves, hll and bdd, at opposite edges for cooperative engagement with the ward plates, it. It is to be particularly noted that the upper ward groove, bte, is of substantial width to accommodate both reduced wards, I 6b and |83, o! the upper ward plate, permitting the key to be inserted into either oi the two groups of master-keyed locks. which are illustrated in section in Figures 6 and 8.

It will be apparent that I can obtain various other rea-arrangements of the master keying and grand master keying features herein disclosed; for example, the nibs on the tumbler elements, might be employed with a cooperating individual or service key, and a key of the type illustrated in Figures 4 and 5 could be either the master" key or a grand master key, while the key disclosed in Figures 1 to 3 of the drawings could also be employed as either the "master key or a grand master" key.

Although the various sections of the lock illustrated in the drawings are several times actual size, it was necessary 'to deviate slightly with respect to certain dimensions of the various features of the lock to more clearly illustrate and emphasize these features. In this connection it may be mentioned that the guard shoulder, 30, of the tumbler element is shown in certain instances a distance away from the adjacent cam surface of the key, something more than the actual dimension which has been found practical for such a construction; and it will be understood that in the commercial form of the lock, the guard shoulder, 30e, will be brought as close as possible to the adjacent cam surface of the key (opposite the cam surface engaging the abutment shoulder of the corresponding tumbler element), and the distance will be more or less determined by the conformation of the cam surfaces of the key, so as to facilitate insertion and withdrawal of the key from engagement with the tumblers of the lock.

I have illustrated diagrammatically in rFigure l of the drawings a hypothetical locking system including several groups of locks operated by individual or service keys, which are indicated in circles bearing the letter S, and certain oi these groups are indicated as being controlled by a master key indicated in circles bearing the letter M, I have further illustrated certain of the masterV-keyed groups to be controlled by a grand master key, indicated in circles bearing letters G. M.; and dually a great grand master key for controlling each of the locks of the entire system, indicated by a circle bearing letters il G. M

Although l have shown and described certain preferred embodiments of my invention, it will be manifest that it is capable of various modications and re-arrangements without departing from the' spirit and scope thereof. I do not wish, therefore, to be understood as limiting myself to the particular construction and arrangement herein shown and described except as indicated in the claims.

I claim:

1. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot and two series of similar tumbler elements mounted in the cylindcr on opposite sides of the key slot, said tumbler elements being mounted for movement transversely to the axis of the cylinder and normally extending into locking engagement with the casing to prevent rotation of the cylinder, the tumbler elements of one series being formed with key-engaging abutment shoulders, and the abutment shoulders of certain of the tumbler elements of said series being disposed in opposite relation to the other tumbler elements of said series, said shoulders being engageable by cooperativelyformed cam surfaces formed on the opposite edges of a key for withdrawing them from locking position, and the tumbler elements o1' the other series having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side of said key for withdrawing the last mentioned series of tumbler elements from locking position.

2. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot and two series of similar tumbler elements mounted in the cylinder on opposite sides of the key slot, said tumbler elements being mounted for movement transversely to the axis of the cylinder and normally extending into locking engagement with the casing to prevent rotation of the cylinder, the tumbler elements of one series being :formed with key-engaging abutment shoulders, and the abutment shoulders of alternate tumbler elements of the series being disposed in opposite relation and adapted to-be engaged by cooperatively-formed cam surfaces formed on the opposite edges of a key lor withdrawing them from locking position, and the tumbler elements of the other series having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side oi said key for withdrawing the last mentioned series of tumbler elements from locking position.

3. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series of `tumbler elements slidably mounted in the cylinder on opposite sides of the key slot, and normally extending into locking engagement with the casing to prevent rotation of the cylinder, the alternate tumblers or" one series being urged in opposite directions, and the abutment shoulders of adjacent tumblers of said series being arranged in opposite relation for engagement by cooperatively formed cam surfaces on opposite edges of the key for withdrawing said series of tumbler elements from locking position, the other series oi tumbler elements having laterally projecting nibs engageable in a cooperatively formed sinuous groove formed in the side of said key for withdrawing said last mentioned series of tumbler elements from locking position.

4. In a lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series of tumbler elements slidably mounted in the cylinder adjacent the key slot, and normally extending into locking engagement with the casing to prevent rotation of the cylinder, both series of tumbler elements being formed with key-engaging abutment features, said abutment features of each series being engageable by separate cooperatively formed surfaces of a key for withdrawing said tumblers from locking engagement with the casing, one of said series of tumbler elements having a second independent series of key-engaging abutment features, engageable and operated by a second key having a cooperatively formed surface, said second key having another cooperatively formed surface for operatively engaging the said abutment features of the other series of tumbler elements for withdrawing all of the tumblers out of locking engagement with the casing.

5. In a lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series of tumbler elements slidably mounted in the cylinder adjacent the key slot, and normally extending lli lil

ditv

mosaico 5 into locking engagement with the casing to prevent rotation of the cylinder, both series of tumbler elements being formed with key-engaging abutment shoulders, and said abutment shoul-I ders of each series being engageable by separate cooperatively formed cam surfaces of a key for withdrawing said tumblers irorn locking engagement with the casing, one oi said series of tumbler elements also being iormed with nibs extending laterally into the key slot, and said nibs being engageable by a second key having a cooperatively iormed sinuous groove, and said second key also having a cooperatively iormed cam surface ior engaging the abutment shoulders oi the other series of tumblers lor withdrag all oi said tumblers oi the loch out oi loclring engagement with the casing.

ii. in a lock including a casing, a cylinder rototably mounted in the casing and having a longitudinally extending key slot, and two series of tumbler elements slidably mounted in the cylinder on opposite sides oi the slot, and normally extending into locking engagement with the casing to prevent rotation ci the cylinder', both. series oi tumblers being iormed with keyengaging abutment ieatures, and said abutment features oi each series being engageable byseparate cooperative formed surlacesoi a hey-iler withdrawing said tumblers iromrgloching engagement with the casing, one ol saidseries oi tumlers having a second independent series of abut- ,Y ment ieatures, engageable and operated by a second lrey having a cooperatively formed sbriace, said second hey having another cooperm atively iormed surface lor engaging the abutment ieatures oi the other series oi tumblers ior withdrawing all oi the tumblers-out ci' loclring engagement with the casing.

' 7. ln a loch including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending lxey slot, and two series oi tumbler elements slidably mounted in the cylinder on opposite sides of the slot and noally extending into loclring engagement with the casing to prevent rotation ol the cylinder, both series oi' tumblers being termed with hey-engaging abutment shoulders,` andA said abutment shoulders oi each series beingfengageable by separate, cooperatively formed cam surfaces oi' a hey for withdrawing said tumblers irorn `lecleing engagement with theA casing, one oi said series oi tumbler elements also being formed with nibs extending-.laterally into the lrey slot, and said nibs being engageable by a second hey having a cooperatively loi-med sinuous groove, and said second key 'also having a cooperatively formed cam suri'ace ior engaging the abutment shoulders of the other series oi tumblers lor withdrawing all oi said tumblers oi' the loch out oi locking engagement with the casing.

t. lin a lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series oi tumbler elements slidably mounted in the cylinder on opposite sides oi the slot, and normally extending into locking engagement with the casing to prevent rotation oi the cylinder, both series ol tumblers being. formed with keyengaging abutment shoulders, and said abutment shoulders of each series being engageable by separate, cooperatively formed cam surfaces of a key-ier withdrawing said ytumblers from locking engagement with the casing, the abutment shoulders of alternate tumbler elements oi one series being disposed in opposite relation,

the other of said series of tumbler elements being formed with nibs extending laterally into the key slot, and said nibs being engageable by a second key having a cooperatively formed sinuous groove, and said second key also having a cooperatively formed cam surface at each edge lor engaging the abutment shoulders oi the ilrst mentioned series oi tumblers, for withdrawm ing all of said tumblers oi the lock out of locking engagement with the casing.

il. In a lock including a casing, a cylinder rotatably mounted in the casi and having a longitudinally extending hey slot, and two series ci tumbler elements slidably mounted in the cylinder on opposite sides oi the slot and normally extending into lockingengagement with the casing to prevent rotation oi the cylinder, both series oi tumbler elements being formed with laterally extending nibs, engageable by a hey having cooperatively iormed sinuous grooves for withdrawing the tumblers from locking engagement with the casing, one oi said series oi bier elements also being provided with a series oi abutment shoulders, said shoulders being engageable by a cooperatively iormed cam surface oi' a second key, and said second key also having a cooperatively formed sinuous groove engageable with the nibs oi the other series ol tumbler elements i'or withdrawing all oi the tumblers out oi loclring engagement with ythe casing. y

lll. In a 'loclr including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending lrey slot, and two series ci tumbler elements slidably mounted in the cylinder on opposite sides oi the slot, and nor-- mally extending into locking engagement'with the casing to prevent rotation oi? the cylinder,

both series oiJ tumbler elements' being formed with laterally extending hey-engaging nibs, one of said series oi. tumbler elements being provided with an independent set of abutment shoulders, said abutment shoulders and said nibs on theother series oi tumbler elements being engagegageable by a key having a cooperatively formed cam surface, said key also having a cooperatively formed sinuous groove for engaging said series of nibs lor withdrawing the tumbler elements irom locking engagement with the casing, the series oi nibs on the series of tumbler elements having the abutment shoulders being engageable by a lrey having cooperatively formed sinuous grooves ior both series oi" nibs on the respective series oi tumbler elements for withdrawing all the 'tumbler elements irom loclring engagement withthe casing.

il. lin a loclr including a casing, a cylinder rotatably mounted in the casing andhaving a longitudinally extending lsey slot, and two series oi tumbler elements slidably mounted in the cylinder at opposite sides oi. the slot and normally extending into locking engagement with the casing to prevent rotation oi the cylinder, both series ol tumbler elements being provided with key-engaging abutment features engageable by cooperatively iormed surfaces of a key adapted lor shifting the tumbler elements from locking position; one oi the series oi' tumbler elements being provided with additional and independent lceyengaging abutment features engageable by a cooperatively formed surface of a second key which is also provided with a cooperatively formed surface ior engaging the aforesaid abutment features oi the other series of tumbler elements for shifting them out of locking position; said other series dit of tumbler elements being also provided with additional and independent key-engaging abutment features, engageable by a cooperatively formed surface of a third key which is also provided with a cooperatively formed surface for engaging the said additional and independent abutment features of the first mentioned series of tumbler elements so that said key will also withdraw all tumblers of the lock from locking position.

l2. In a lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series oi tumbler elements slidably mounted in thecylinder at opposite sides of the slot and normally extending into locking engagement with the casing to prevent rotation of the cylinder, both series of. tumbler elements being provided with laterally projecting nibs extending into the key slot engageable by cooperatively formed sinuous grooves in the side surfaces of a key adapted for shifting the tumbler elements from locking position; one of the series of tumbler elements being provided with additional and independent key-engaging abutment features engageable by a cooperatively formed surface of a second key, which is also provided with a cooperatively -formed sinuous groove for engaging the nibs of the other series of tumbler elements for shifting them out of locking position; said other series of tumbler elements being also provided with additional and independent key-engaging abutment features engageable by a cooperatively formed surface of a third key which is also provided with a cooperatively ormed surface for engaging the said additional and independent abutment features oi the iirst mentioned series of tumbler elements so that said key will also withdraw all tumblers of the lock from locking position.

i3. "in a lock including a casing, a cylinder rotatably mounted in the .casing and having a longitudinally extending key slot, and two series ci tumbler elements slidably mounted in the cylinder at opposite sides oi the slot and normally extending into locking engagement with the casing to prevent rotation of the cylinder, both series of tumbler elements being provided with laterally projecting nibs extending into the key slot engageable by cooperatively formed sinuous grooves in the side surfaces oi a key adapted :or shifting the tumbler elements from locking position; one of the series of tumbler elements being also provided with key-engaging abutment shoulders engageable by a cooperatively formed cam surface of a second key which is also provided with a cooperatively iormed sinuous groove for engaging the nibs of the other series of tumbler elements for shifting them out of locking position; said other series of tumbler elements being also provided with key-engaging abutment shoulders engageable by a cooperatively formed cam surface of a third key which is also provided with a cooperatively formed cam surface for engaging the said abutment shoulders of the first mentioned series of tumbler elements so that said key will also withdraw al1 tumblers of the lock from locking position.

14. In a lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot, and two series of tumbler elements slidably mounted in the cyllinder on opposite sides of the key slot and normally extending into locking engagement with the casing to prevent rotation of the cylinder, both series of tumbler elements being provided with key-engaging abutment features adapted to be engaged by cooperatively formed surfaces of a key for withdrawing said tumblers from locking position, the key slot of the cylinder being provided with a ward engageable in a cooperatively formed groove of vthe key, said tumbler elements also being withdrawable from locking position bya second key having a ward groove for cooperating with the ward in said key slot, said key being formed to also withdraw the tumbler elements of another lock cylinder having a diiierently located ward.

l5. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot and two series of tumbler elements slidably mounted in the cylinder on opposite sides of the key slot, and normally extending into locking engagement with the casing to prevent rotation of the cylinder, the alternate tumblers o1 one series being urged in opposite directions, the abutment shoulders oi adjacent tumblers of said series being arranged in opposite relation for engagement by the cooperatively formed cam surfaces on opposite edges oi the key for withdrawing said series of tumbler elements from locking position, and the tumbler elements of the other series being arranged so that each is urged in a direction opposite to that of the transversely adjacent tumbler of the lrst mentioned series, said other series of tumbler elements having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side oi said key for withdrawing said last mentioned series or" tumbler elements from locking position.

i6. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot and two series oi tumbler elements slidably mounted in the cylinder on opposite sides of the key slot, and nor mally extending into locking engagement with the casing to prevent rotation of the cylinder, the transversely adjacent tumblers ot' the respective series being movable in relatively opposite directions for release from locking position, the tumblers of one series having abutment shoulders adapted to be engaged by a cooperatively formed earn surface on the edge of a key for withdrawing said series of tumblers from locking position, and the other'series of tumbler elements having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side of said key for withdrawing the last mentioned series of tumblers from locking position.

17. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot and two series oi' tumbler elements slidably mounted in the cylinder on opposite sides oi.' the key slot, and normally extending into locking engagement with the casing to prevent rotation of the cylinder, the a1- ternate tumblers of each series being movable in opposite directions for release from locking position, the tumblers of one series having abutment shoulders adapted to be engaged by cooperatively formed cam surfaces on the edges of a key for withdrawing said series of tumblers from locking position, and the other series of tumbler elements having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side of said key for withdrawing the last mentioned series of tumblers from locking position.

18. A lock including a casing, a cylinder rotatably mounted in the casing and having a longitudinally extending key slot with two series ot tumbler elements slidably mounted in the cylinder on opposite sides of the key slot respectively, one tumbler of each series being disposed directly opposite a tumbler of the other series, said tumblers normally extending into locking engagement with the casing to prevent rotation of the cylinder, one series of tumbler elements being formed with abutment shoulders adapted to loe engaged by a cooperatively formed cam surface on the edge of a key for withdrawing said series of tumlers from locking position, and the other series having laterally projecting nibs engageable in a cooperatively formed sinuous groove in the side of such key for withdrawing the lastmentioned series of tumblers from locking position.

JOHN F. SVOBODA. 

